Salty soils affect the growth of plants worldwide, particularly in irrigated land where one-third of the world's food is produced. It is estimated that one-fifth of irrigated land is salt-affected. And it is a problem that is only going to get worse as pressure to use more water increases and the quality of water decreases. Helping plants to withstand this salty onslaught would have a significant impact on world food production.

Salt in the soil also affects dryland agriculture, particularly in semi-arid regions of the world, such as in the Middle East, Kazakhstan and Australia. 70% of Australia's wheat crop is affected by salt that is found as much a metre beneath the surface – this is important, as Australia is one of the world's largest exporters of wheat.

Any approaches which can be taken to reduce the impact of salinity on world food production would be valuable. The world food situation is now critical. More than one billion people now go hungry each day. World grain stores are now lower than they have been for fifty years, since before the Green Revolution. Reflecting this, prices have increased greatly. Pressures from increasing population, increasing standards of living and biofuels, all in the context of global climate change, are making demands that are increasingly difficult to meet.

The inequitable distribution of food is, of course, very important, as are problems of distribution of better seed varieties and basic farming technologies to farmers. These are perennial issues which intergovernmental organisations (such as the Consultative Group on International Agricultural Research) and charities (eg the Rockefeller Foundation) have battled valiantly to address for decades. And support for this must continue. But despite such wonderful work and many local victories, the problems globally are getting worse, not better. We need more and, perhaps, different strategies – including new technologies.

In my group's research over the past ten years, we have been studying the mechanisms plants use to tolerate salinity, and how to manipulate these processes so that plants can keep growing while the salt keeps rising.

We have generated plants that are much more tolerant to salt, work which was published yesterday.

One mechanism of salinity tolerance involves keeping the toxic sodium ion (Na+) out of the leaves. One way to do this is to reduce the amount of Na+ moving from the roots to the shoots in the stream of water that flows up through the plant's water conducting pipes.

We made a targeted genetic tweak so that Na+ is removed from the water flowing up the stem before it reaches the shoot – once out, it is stuck. The effect of this manipulation is to reduce the amount of toxic Na+ building up the shoot and so increase the plant's tolerance to salinity.

The control of the gene we manipulated is crucial. To be effective, it must be tuned up so that it works harder and produces more protein than it usually would specifically around the plant's water conducting tubes in the mature root. In doing this, we have enhanced a process used naturally by plants to minimise the movement of Na+ to the shoot. We have used genetic modification (GM) to amplify the process, helping plants to do what they already do – but to do it much better!

We are now in the process of transferring the technology to crops such as rice, wheat and barley. And results in rice already look very promising.

The motivation for my research is as an independent academic seeking knowledge and its application for public good. It is driven by the same imperatives that led me to be an active member of the UK Green party for nearly a decade. As such, I consider my funding sources to be irrelevant to my academic integrity. Nevertheless, I can declare that none of our research on salinity has been paid for by industry. All funding has been from UK, EU or Australian governmental sources or from charities such as the Leverhulme Foundation. Furthermore, the outputs described in the paper are fully and freely available for public benefit. I hope very much that the principles of our work can be applied to develop salt-tolerant crops in developing countries and give farmers on low-quality soils a better chance at improving their lot.

And giving people a chance to better their situation is something we need to facilitate, not impede. The west may not need more food, but remember Make Poverty History – a child dies unnecessarily as a result of extreme poverty every three seconds. GM crops are not the answer to this shameful global situation, but I argue strongly that they provide another tool, another option to try to address the problem. And I do not think those of us sitting in comfortable wealth have a right to deny people the opportunity to improve their production of food. The technology is just that, a technology. Like nuclear technologies (radiotherapy or nuclear weapons) or mobile phones (communication or bomb triggers), how we use it is the main issue. I hope that the plants we have generated provide a subtle use of GM technology that will allow some positive benefits for the developing world.

Prof Mark Tester started working on mechanisms of salinity tolerance at the University of Cambridge, and has continued this over the past five years at the Australian Centre for Plant Functional Genomics and the University of Adelaide in Australia. His research also includes increasing the efficiency of nitrogen in crops and the concentration of iron and zinc in rice grain – to address the world's biggest health problem, micronutrient deficiency.